1. AGRICULTURE and HUMAN IMPACT on the BIOSPHERE Chapter 6

3. WORLD POPULATION Current world population is over _____________
Image from:
WORLD POPULATION
World clock
Current world population is over _____________
Estimates predict it will reach billion by _______
7 BILLION
2050

4. Does this look familiar?
What is the Earth’s carrying capacity? ?

5. SUSTAINABILITY How can we grow enough food for all the people on the planet without destroying the environment?

6. Importance of Agriculture
By middle of 20th century, despite agricultural advances there were ________________in many parts of the world.
Governments and scientists began a major effort to ___________ food production
food shortages
increase

7. __________ REVOLUTION
GREEN
__________ REVOLUTION
strains
New plant ________ had higher yield & resisted pests
2. Modern farming__________
allowed planting larger areas
3. Chemical ___________ & ___________ boosted crop production and controlled pests
techniques
fertilizers pesticides

8. HOW DO WE GROW MORE FOOD? Large fields are planted with a
single variety
year after year
= ____________
MONOCULTURE

9. Allows farmers to grow large quantities of food BUT . . .
MONOCULTURE
Allows farmers to grow large quantities of food BUT . . .

10. But . . . HAS HUGE IMPACT ON ECOSYSTEMS
__________ increase yield BUT RUNOFF can cause algal blooms and ____________
Fertilizers
DEAD ZONES

11. But . . . HAS HUGE IMPACT ON ECOSYSTEMS
________ kill insects that damage crops BUT . . .
they kill ________ insects too
Pesticides
beneficial
Bees
Hand pollination

12. _____ was first modern insecticide
Example:
_____ was first modern insecticide
It was cheap, stayed active for long time, and killed many different insects
Used to control agriculture pests
and disease carrying
_______________
DDT
MOSQUITOES

13. http://www. ci. cypress. ca
When DDT was sprayed,
runoff carried it into rivers
and streams in LOW
concentrations.
DDT then passes into
organisms through the
___________, is stored
in _______, and
doesn’t ___________.
food chains
tissues
degrade

14. → → BIOLOGICAL MAGNIFICATION ______________________________
= the ____________ of a harmful substance
____________as it passes to organisms at
_______________levels in food chain or web.
concentration
increases
higher trophic
Plants pick up
DDT from water
& store it
Herbivores eat
plants and store some DDT
Carnivores eat
herbivores and store more DDT → →

16. The wide spread use of DDT threatened many species… especially fish eating birds like osprey, brown pelican, and
bald eagles.
DDT causes birds to lay
eggs with ___________
shells so eggs would
break when sat on.
American Bald Eagle was declared
endangered in It has since been
reclassified as _____________________
fragile
“threatened”

17. told of DDT’s harmful effects.
In 1962, American biologist _______________ published the book,_____________ which
told of DDT’s harmful effects.
The book led to a large public outcry and eventually resulted in DDT being _________ in the United States in the 1970’s
The book was one of the important events in the birth of the _________________________.
Rachel Carson
Silent Spring
banned
environmental movement

18. But . . . HAS HUGE IMPACT ON ECOSYSTEMS
Wearing away of topsoil = _________ is caused by plowing land and removing plant roots
Soil erosion

19. But . . . HAS HUGE IMPACT ON ECOSYSTEMS
________ from feedlots and fields can contaminate surface and ground water
____________ happens to clear trees for beef farms
Raising cows uses lots of ______ and releases ________ into the atmosphere increasing climate change.
Runoff
Deforestation
water
methane

20. Impact of Agriculture
______________ = changing of fertile land in dry climates into desert areas caused by farming, overgrazing, and drought
Desertification

21. But . . . HAS HUGE IMPACT ON ECOSYSTEMS
Many Midwest states rely
on the _________ aquifer
for their water needs.
We are using water faster than the ______cycle can replace it.
Evidence indicates this aquifer may _________ within years.
OGALLALA
water
run dry

22. HOW DO WE HELP? technology
Modern_________ is changing how farmers farm and lessening the impact on the environment.
EX:
__________ imaging
_____ technology
enable farmers to
only apply chemicals
where__________
Satellite
GPS
needed

23. HOW DO WE FIX IT? “No-till”
________ keeps plant residue in fields Reduces __________ and protects ecosystems from runoff
soil erosion

24. HOW DO WE FIX IT?
Planting legumes, alfalfa, grasses and other __________ keeps plants on soil between food crops reduces __________ and protects ecosystems from runoff
- reduces ______ - reduces need for fertilizer
Cover crops
soil erosion
weeds

25. HOW DO WE FIX IT? Crop rotation
______________ alternates what is crops are planted each year.
- helps control ________ without pesticides
- alternating with __________ replenishes soil nutrients without fertilizer
insects
legumes

26. HOW DO WE FIX IT? Controlled grazing
________________ = managing graze periods and herd densities
- improves nutrient cycling retains water ________ desertification
prevents

27. HOW DO WE FIX IT? Biological __________ pest control
uses natural predators like insects or spiders to kill insects instead of chemical pesticides
Biological

28. HOW DO WE FIX IT? Contour plowing
_______________ = on hilly areas, plowing is done across the hill rather than straight up and down
- prevents soil _______ from runoff
Contour plowing
erosion

29. WHAT CAN YOU DO? - Eat _____ meat
- Don’t ______ food ~ 1/3 of all food produced worldwide, ($1 trillion) gets lost or wasted ~ US avg: 20 lbs/person/month wasted
LESS
Per capita/year
waste
Food waste

30. WHAT CAN YOU DO? Be aware of ___________ water
Water the is used to produce products that we don’t know or don’t think about
INVISIBLE
The PRODUCTION OF:
1 kg wheat costs 1,300 L water
1 kg rice costs 3,400 L water
1 kg eggs costs 3,300 L water
1 kg beef costs 15,000 L water
1 cotton shirt costs 2,500 L water
1000 g of blue jeans costs 10,850 liters water
1 ton passenger car costs 400,000 liters of water
Building a house uses about 6 million liters of water
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